EP2431597B1 - Method and device for detecting a fuel in a fuel supply system of a combustion engine - Google Patents

Description

The invention relates to a method for detecting a viscosity of a fuel in a fuel supply system of an internal combustion engine, according to the preamble of claim 1. The invention further relates to a fuel supply system having a device for determining the viscosity of a fuel in the fuel supply system of an internal combustion engine, according to the preamble of patent claim 15th

The use of other liquid fuels or mixtures thereof as the typical fuels, such as diesel and gasoline mixtures, requires in the corresponding engine control strategies for controlling and optimizing the combustion. For the application of the control strategies, the detection of the respectively present in the fuel supply system fuel or the fuel mixture is necessary.

In the operation of an internal combustion engine with different types of fuel or fuels is for the simultaneous fulfillment of the objectives comfort, emissions and consumption, a determination of the decisive for combustion fuel characteristics (e.g., cetane number and Siedelage) of each currently present in a fuel supply system fuel necessary. This fuel currently present in the fuel supply system is, for example, a pure fuel, such as diesel, gasoline, naphtha, kerosene, alcohol, butanol, in particular methanol, GTL (gas to liquid) or BTL (biomass to liquid), or a mixture of at least two clean fuels.

From the DE 10 2007 052 096 B4 is a method for detecting a type of fuel, which is injected via an injection system in a combustion chamber of an internal combustion engine, known. In this case, in a high-pressure region of the injection system, a pressure is measured over time and, in phases during which the high-pressure pump does not deliver fuel, integrated the balance equation of the hydraulic system over a period considered. From characteristic curves of the compressibility module and the density in, known for each fuel Depending on the pressure, the pressure difference is determined from the integrated balance equation using the values for compressibility modulus and density determined from these characteristics at a pressure measured in the injection phase in a trial-and-error procedure. The pair of compressibility module and density which best reproduces the pressure difference measured over the considered time range is used to detect the fuel. In other words, within a delivery pause of a fuel pump, a defined injection is triggered with a known amount from a map. Since not nachgefördert, the compressibility of the fuel causes the amount of known pressure and known temperature. The different compressibilities and densities of the different expected fuels are listed in tables. This can be closed by means of the known volume of the high-pressure region of the injection system to the existing fuel.

From the DE 10 2008 026 009 A1 For example, a method for determining the viscosity and elasticity of viscoelastic media by means of acoustoelectric resonators is known. In this case, a function which describes the electrical admittance of the acoustoelectric resonator is optimized by iteratively adapting this function to a measured admittance curve of the acoustoelectric resonator with measurement medium applied thereto. The adjusted function can then be the viscosity and elasticity of the medium to be taken as a parameter.

From the DE 10 2004 008 150 A1 An on-board measurement of fuel properties for engine management is known. In this case, a defined volume of fuel is evaporated by means of a heater. The time and heating energy required for this is measured and used to determine a fuel distillation performance index (DI). The DI value is a measure of fuel volatility and is then used to control the operation of the engine to reduce pollutants and improve performance.

From the DE 40 19 187 C2 It is known to determine a fuel composition by means of a capacitive dielectric sensor which measures the dielectric constant of the fuel.

In the DE 10 2007 034585 A1 and the JP 63 313065 A discloses that properties of fluids, including the viscosity of a fuel, can be determined by moving a body with a defined force through the fluid and is closed by the time required for a defined path travel time of the body on the viscosity.

The invention has for its object to provide a simple and accurate method for determining the viscosity of a fuel supplied to an internal combustion engine.

This object is achieved by a method of o.g. Art having the features characterized in claim 1 and by a fuel supply system of the above-mentioned. Art solved with the features characterized in claim 15. Advantageous embodiments of the invention are described in the further claims.

For this it is in a procedure of o.g. Art according to the invention provided that a displacement body is moved in a bubble filled with the fuel in the fuel supply system of the internal combustion engine cavity from a first predetermined position to a second predetermined position, wherein from the time required for the movement movement and / or from the movement with a viscosity of the fuel present in the fuel supply system of the internal combustion engine is determined at a predetermined speed, the fuel is supplied to the parallel to a fuel line integrated into the fuel supply system cavity by means of an inlet and a 2/2-way valve from the fuel line and by means of a Runoff and a check valve of the fuel line is fed back.

This has the advantage that, with low complexity, a functionally reliable detection of properties of the fuel relevant for combustion in the internal combustion engine is available by means of the viscosity.

A particularly good dependence of the movement time and / or the motive force on the viscosity of the fuel in the fuel supply system of the internal combustion engine is achieved in that the displacer is moved in the cavity such that in a gap between the displacer and the cavity, a shear flow of the fuel results.

A particularly accurate determination of the viscosity by means of a movement time over a predetermined distance with constant motive force is achieved by moving the displacer in the form of a piston in the cavity in the form of a capillary tube, the plunger being driven by a spring with constant motive force from the first predetermined one Position moves to the second predetermined position and the movement time for the movement from the first predetermined position to the second predetermined position is determined.

A precise determination of the viscosity in a mechanically simplified construction is achieved by moving the displacer in the form of a piston in the cavity in the form of a cylinder open on both sides in such a way that a shear flow results between the piston and the cylinder, the piston being constant Speed is moved from the first predetermined position to the second predetermined position and the movement force required for the movement from the first predetermined position to the second predetermined position is determined.

A further improvement in the accuracy of the determination of the viscosity is achieved in that the displacement body is moved in the form of a membrane piston in the cavity in the form of a capillary tube, the diaphragm piston of a spring with a constant motive force (known force-displacement curve is sufficiently constant; Force ideal) is moved from the first predetermined position to the second predetermined position and the movement time for the movement from the first predetermined position to the second predetermined position is determined.

A bubble-free flow through the cavity with fuel from the fuel supply system of the internal combustion engine is achieved, for example, that a flow of fuel into the cavity via a 2/2-way valve fluidly connected to the fuel supply system of the internal combustion engine and that a drain for fuel from the Cavity is fluidly connected via a check valve with the fuel supply system of the internal combustion engine.

A particularly fast and reliable determination of the density of the fuel is achieved by reading out the viscosity from a table in which the assignments of travel time and / or motive force are stored with the viscosity of the fuel.

A determination of different types of fuel in the fuel, which is present in the fuel supply system of the internal combustion engine, obtained by the fact that from the specific viscosity all present in the fuel in the fuel supply system of the internal combustion engine fuel types, in particular diesel, gasoline, naphtha, kerosene, alcohol, Butanol, in particular methanol, GTL (gas to liquid) or BTL (biomass to liquid), are determined.

For optimum setting of parameters for the combustion, such as injection timing and / or activation duration, with regard to the currently present in the fuel supply system of the internal combustion engine fuel from the determined viscosity at least one engine-relevant parameter, in particular a cetane number and / or a boiling position of the fuel determined the fuel supply system of the internal combustion engine.

To correct the coefficient of expansion of the fuel, a temperature of the fuel in the region of the displacer and / or a temperature of the displacer is determined simultaneously with the determination of the viscosity, and the viscosity is additionally determined as a function of the temperature. In this case, a viscosity of the fuel at a predetermined standard temperature, in particular 15 ° C., is preferably determined by means of the specific temperature.

A particularly rapid and effective adaptation of the combustion to the fuel present in the fuel supply system of the internal combustion engine achieved by the fact that for predetermined multi-fuel mixtures, in particular mixtures with at least two of the fuel types diesel, gasoline, naphtha, kerosene, butanol, GTL (gas to liquid) or BTL (biomass to liquid), an energy injection quantity is corrected as a function of the specific viscosity.

Furthermore, in an apparatus of a fuel supply system of the above-mentioned. Art according to the invention provided that it has a bubble-free fillable with the fuel cavity in which a displaceable from a first predetermined position to a second predetermined position displacer is arranged, wherein the cavity is integrated in parallel to a fuel line in the fuel supply system and wherein the cavity means an inlet for the fuel and a 2/2-way valve and by means of a drain for the fuel and a check valve is fluidly connected to the fuel line.

This has the advantage that a simple determination of the viscosity of the fuel over a movement time of the displacer at constant acting on this moving force and / or acting on the displacer movement force for a predetermined translational movement, for example, a translational movement at a predetermined speed is achieved.

A particularly high correlation between the movement of the displacer and the viscosity of the fuel present in the cavity is achieved in that the cavity and the displacer are arranged and formed such that upon movement of the displacer in a gap between the displacer and the cavity forms a shear flow.

A mechanically particularly simple structure is achieved in that the displacer is a piston or a diaphragm piston.

A determination of the viscosity of the fuel present in the cavity by means of a movement time for a movement of the displacement of the first predetermined position to a second predetermined position is achieved in that in the cavity, a mechanical spring means, in particular a coil spring, leaf spring or a gas spring, such is arranged and designed such that this mechanical spring means moves the displacer with a predetermined motive force from the first predetermined position to a second predetermined position.

A determination of the viscosity of the fuel present in the cavity by means of a necessary motive force for movement of the displacer from the first predetermined position to a second predetermined position at a predetermined speed can be achieved by arranging and forming in the cavity a mechanical translating device said mechanical translating means moves the displacer at a predetermined speed from the first predetermined position to a second predetermined position.

In order to obtain as void-free as possible fuel in the cavity, it can be provided, the device according to the invention as a closed system, i. only with connections (inlet and outlet) to lines of the fuel system or without connection to the atmosphere form. This provides the preferred possibility of keeping the fuel in the cavity under pressure, which effectively prevents (vapor) bubble formation.

The provision of the fuel under pressure can be achieved by arranging the device according to the invention in a fuel supply system according to the invention, which comprises, in addition to the device, at least one fuel tank, the fuel line and a return for the fuel, downstream of a pump (for the fuel). at the pump may preferably be a low pressure pump such as a prefeed pump.

Fig. 1

eine erste bevorzugte Ausführungsform eines erfindungsgemäßen Kraftstoffzuführungssystems einer Brennkraftmaschine mit einer Vorrichtung zum Ausführen des erfindungsgemäßen Verfahrens in einem schematischen Blockschaltbild ,

Fig. 2

eine zweite bevorzugte Ausführungsform eines erfindungsgemäßen Kraftstoffzuführungssystems mit einer Vorrichtung zum Ausführen des erfindungsgemäßen Verfahrens in einem schematischen Blockschaltbild und

Fig. 3

eine dritte bevorzugte Ausführungsform eines erfindungsgemäßen Kraftstoffzuführungssystems mit einer Vorrichtung zum Ausführen des erfindungsgemäßen Verfahrens in einem schematischen Blockschaltbild.

The invention will be explained in more detail below with reference to the drawings. These show in

Fig. 1

A first preferred embodiment of a fuel supply system according to the invention of an internal combustion engine with an apparatus for carrying out the method according to the invention in a schematic block diagram,

Fig. 2

a second preferred embodiment of a fuel supply system according to the invention with an apparatus for carrying out the method according to the invention in a schematic block diagram and

Fig. 3

A third preferred embodiment of a fuel supply system according to the invention with an apparatus for carrying out the method according to the invention in a schematic block diagram.

Fig. 1 shows by way of example and schematically a fuel supply system of an otherwise not shown internal combustion engine with a fuel tank 10, a prefeed pump 12, a fuel line 14, a filter 16, a high-pressure pump 18, a common rail 20, an injector 22 for each working cylinder (not shown) of the internal combustion engine , a first return 24 from the injector 22 into the fuel tank 10 and a second return 26 from the common rail 20 into the fuel tank 10.

In the Fig. 1 illustrated, the first preferred embodiment of a device for determining the viscosity of a fuel in a fuel supply system of an internal combustion engine according to the invention for carrying out the method according to the invention comprises a cavity 28 in the form of a capillary tube, in which a displacement body 30 is arranged in the form of a piston. The piston is movable by a spring 32 from a first predetermined position 44 within the cavity 28 to a second predetermined position 42 within the cavity 28 at a predetermined constant motive force. An inlet 34 for fuel connects the cavity 28 in fluid communication with the fuel line 14 via a 2/2-way valve 36 and a drain 38 for fuel connects the cavity 28 in fluid communication with the fuel line 14 via a check valve 40. About the inlet 34 and the Outflow 38 flows fuel from the fuel supply system via the cavity 28 and fills it bubbles. An electromagnet 46 moves the piston against a restoring force of the spring 32 in the first predetermined position 44. The spring 32 applies a predetermined motive force to the piston from the first predetermined position 44 through the fuel in the cavity 28 through a distance 48 to the second predetermined position 42, where a detector 50, such as a microswitch, detects the arrival of the piston at the second predetermined position 42. In Fig. 1 30 denotes the piston at the second predetermined position 42, 30 ', the piston at a position between the first and second positions 42, 44 and 30 "the piston at the first predetermined position 44th

A movement time required for this translational movement of the piston from the first predetermined position 44 to the second predetermined position 42 is measured, and from this movement time, a viscosity of the fuel in the cavity 28 is determined. The viscosity is then used to conclude a mixture of the fuel from various fuel types, such as diesel, gasoline, naphtha, kerosene, alcohol, in particular methanol, butanol, GTL (gas to liquid) or BTL (biomass to liquid). For this purpose, for example, appropriate tables are provided with assignments of mixing ratios and viscosities. If necessary, directly corresponding combustion-relevant properties of the fuel are also determined from the viscosity.

A temperature compensation is provided for example with a standard existing fuel temperature sensor. By the 2/2-way valve 36 and the check valve 40 ensures that the representative of the tank 10 mixture in the measuring system (free of gas bubbles) is present and that the measurement result is not affected by undefined flow.

Optionally, the piston and the cavity 28 are formed such that a gap 52 results between the two. Through this gap 52 results in a shear flow of the fuel during the movement of the piston.

Fig. 2 shows a second preferred embodiment of a fuel supply system according to the invention, with an apparatus for carrying out the method according to the invention, wherein functionally identical parts are designated by the same reference numerals, as in Fig. 1 so that their explanation to the above description of Fig. 1 is referenced. In contrast to the first embodiment according to Fig. 1 the cavity 28 is formed as an open cylinder and the piston is at a predetermined speed through the cavity 28 moves. The movement force 54 required for this purpose is measured, and from this motive force 54 a viscosity of the fuel in the cavity 28 is determined. This viscosity of the fuel thus determined becomes corresponding as in relation to Fig. 1 further evaluated to determine fuel properties and mixing proportions of fuel types in the fuel.

The correlation between viscosity and the required motive force for the translational movement of the piston in the "open" cylinder 28 results, in particular, from the fact that a shear flow 56 in the gap 52 between piston and cylinder 28 changes depending on the viscosity. A temperature compensation is provided for example with the standard existing fuel temperature sensor. The measuring volume is the same as in the first embodiment Fig. 1 To protect against cross-influences by flow, eg by execution as a closed system.

Fig. 3 shows a third preferred embodiment of a fuel supply system according to the invention with an apparatus for carrying out the method according to the invention, wherein functionally identical parts are designated by the same reference numerals, as in Fig. 1 so that their explanation to the above description of Fig. 1 is referenced. In contrast to the first embodiment according to Fig. 1 the displacement body 30 is formed as a diaphragm piston and there is no gap 52 is provided.

The spring-loaded displacer 30 in the form of the membrane piston, arranged in the capillary tube 28, points after tightening e.g. by the solenoid valve 46 in response to the viscosity of the fuel at a constant spring restoring force on a characteristic, measurable return time or movement time. A temperature compensation is provided for example with the standard existing fuel temperature sensor. The spring is represented for example by an enclosed gas volume 32 '(gas spring).

The bias of the diaphragm piston is designed, for example, such that the diaphragm piston actuates the detector 50 in the state tensioned by the spring forces. The time between the states "E-magnet 46 de-energized" and "microswitch 50 actuated" is characteristic taking into account the fuel temperature in the measuring system for the viscosity of the fuel present in the measuring system. This thus determined from the movement time viscosity of the fuel is, as in relation to Fig. 1 further evaluated to determine fuel properties and mixing proportions of fuel types in the fuel.

The device is installed within a component of the fuel supply system according to the invention (tank 10, low pressure line 14, common rail 20, injector 22 or filter 16), which flows through well. For a binary fuel mixture, the viscosities of the individual fuels and the mixed viscosity are known. From the measured viscosity of the fuel in the cavity 28 can be so, possibly after a temperature correction, determine the mixing ratio of fuel types in the fuel. The temperature correction compensates for the sharp drop in viscosity with the increase in temperature.

The devices are as in the Fig. 1 and 3 represented, preferably formed as closed systems, whereby the freedom from bubbles of the fuel to be analyzed can be ensured. In particular, it is possible to pressurize the fuel in the device with a defined (over) pressure in order to assist in obtaining a bubble-free fuel. Moreover, the fact that the device is preferably integrated into a portion of the fuel supply system, in which at least a portion of the fuel is pumped through the fuel tank permanently in a cycle, ensures that always, for example, after a refueling, the fuel supplied to the injectors also is actually analyzed.

Alternatively, in addition, a combination with a method for detecting a fuel in a fuel supply system of an internal combustion engine, wherein a resonant frequency of an oscillated by the fuel in the fuel supply system of the internal combustion engine oscillator quartz determines and from the resonant frequency, a density of the fuel in the fuel supply system of the internal combustion engine is determined.

This has the advantage that with low complexity, a functionally reliable and rapid detection of relevant for the combustion in the internal combustion engine properties of the fuel is available.

A particularly simple and functionally reliable determination of the density of the fuel is achieved by comparing the specific resonance frequency with a resonant frequency of the quartz crystal in a reference medium, in particular in vacuum or air, and from a difference between these two resonance frequencies, the density of the fuel in the fuel supply system Internal combustion engine is determined.

A particularly fast and functionally reliable determination of the density of the fuel is achieved by reading the density from a table or by determining a known functional equation in which the resonance frequency and density of the fuel are assigned.

A determination of different types of fuel in the fuel, which is present in the fuel supply system of the internal combustion engine, obtained by the fact that from the specific density all present in the fuel in the fuel supply system of the internal combustion engine fuel types, in particular diesel, gasoline, naphtha, kerosene, alcohol, especially methanol, butanol, GTL (gas to liquid) or BTL (biomass to liquid).

For optimal setting of parameters for the combustion, such as injection timing and / or injection parameterization, with regard to the currently present in the fuel supply system of the internal combustion engine from the specific density at least one engine-relevant parameter, in particular a cetane number and / or a boiling position, the fuel in determined the fuel supply system of the internal combustion engine.

To correct the expansion coefficient of the fuel, a temperature of the fuel in the region of the quartz crystal and / or a temperature of the quartz crystal is determined simultaneously with the determination of the resonant frequency, and the density is determined as a function of the resonant frequency and the temperature. In this case, a density of the fuel at a predetermined standard temperature, in particular 15 ° C., is preferably determined by means of the specific temperature.

A particularly rapid and effective adaptation of the combustion to the fuel present in each case in the fuel supply system of the internal combustion engine is achieved in that for predetermined multi-fuel mixtures, in particular mixtures with at least two of the fuel types diesel, gasoline, naphtha, kerosene, GTL (gas to liquid) or BTL ( biomass to liquid), butanol, an energy injection quantity is corrected as a function of the specific resonance frequency.

LIST OF REFERENCE NUMBERS

10

Fuel tank

12

prefeed

14

Fuel line

16

filter

18

High pressure pump

20

Common rail

22

injector

24

first return

26

second return

28

cavity

30

Displacer at the second predetermined position 42nd

30 '

Displacer between the first predetermined position 442 and second predetermined position 42nd

30 "

Displacer at the first predetermined position 44th

32

feather

32 '

Gas spring

34

Intake

36

2/2 way valve

38

procedure

40

check valve

42

second predetermined position

44

first predetermined position

46

electromagnet

48

path

50

detector

52

gap

54

moving force

56

shear flow

Claims (22)

1. Method for detecting the viscosity of a fuel in a fuel supply system of an internal combustion engine, wherein an expeller body (30) is moved into a cavity (28), filled without bubbles with the fuel in the fuel supply system of the internal combustion engine, from a first predetermined position (44) to a second predetermined position (42), wherein a viscosity of the fuel which is present in the fuel supply system of the internal combustion engine is determined from the movement time necessary for the movement and/or from the movement force which is necessary for the movement with a predetermined speed, characterized in that the fuel is supplied to the cavity (28) integrated into the fuel supply system parallel to a fuel line (14), by means of an inflow (34) and via a 2/2-way valve (36) from the fuel line (14) and is fed back to the fuel line (14) by means of an outflow (38) and via a non-return valve (40).
2. Method according to Claim 1, characterized in that the expeller body (30) is moved in the cavity (28) in such a way that a shear flow of the fuel is produced in a gap (52) between the expeller body (30) and the cavity (28).
3. Method according to at least one of the preceding claims, characterized in that the expeller body (30) in the form of a piston is moved in the cavity (28) in the form of a capillary tube, wherein the piston is moved by a spring (32) with a constant movement force from the first predetermined position (44) into the second predetermined position (42), and the movement time for the movement from the first predetermined position (44) into the second predetermined position (42) is determined.
4. Method according to at least one of Claims 1 and 2, characterized in that the expeller body (30) in the form of a piston is moved in the cavity (28) in the form of a cylinder which is open on both sides in such a way that a shear flow is produced between the piston and the cylinder, wherein the piston is moved with a constant speed from the first predetermined position (44) into the second predetermined position (42), and the movement force which is necessary for this for the movement from the first predetermined position (44) into the second predetermined position (42) is determined.
5. Method according to at least one of Claims 1 and 2, characterized in that the expeller body (30) in the form of a diaphragm piston is moved in the cavity (28) in the form of a capillary tube, wherein the diaphragm piston is moved by a spring (32) with a constant movement force from the first predetermined position (44) into the second predetermined position (42), and the movement time for the movement from the first predetermined position (44) into the second predetermined position (42) is determined.
6. Method according to at least one of the preceding claims, characterized in that an inflow for fuel leading to the cavity (28) is connected in a fluid-conducting fashion to the fuel supply system of the internal combustion engine via a 2/2-way valve (36).
7. Method according to at least one of the preceding claims, characterized in that an outflow for fuel out of the cavity (28) is connected in a fluid-conducting fashion to the fuel supply system of the internal combustion engine via a non-return valve (40).
8. Method according to at least one of the preceding claims, characterized in that the viscosity is read out from a table or determined from a set of equations in which assignments of movement time and/or movement force to the viscosity of the fuel are stored.
9. Method according to at least one of the preceding claims, characterized in that all the types of fuel, in particular diesel, petrol, naphtha, kerosene, butanol, alcohol, in particular methanol, GTL (gas to liquid) or BTL (biomass to liquid) which are present in the fuel in the fuel supply system of the internal combustion engine are determined from the determined viscosity.
10. Method according to at least one of the preceding claims, characterized in that at least one engine-relevant parameter, in particular a cetane number and/or a boiling point of the fuel in the fuel supply system of the internal combustion engine is determined from the determined viscosity.
11. Method according to at least one of the preceding claims, characterized in that at the same time as the determination of the viscosity a temperature of the fuel in the region of the expeller body (30) and/or a temperature of the expeller body (30) is determined, and the viscosity is additionally determined as a function of the temperature.
12. Method according to Claim 11, characterized in that a viscosity of the fuel at a predetermined standard temperature, in particular 15°C, is determined by means of the determined temperature.
13. Method according to at least one of the preceding claims, characterized in that an energetic injection quantity for predetermined mixtures of additional fuel, in particular mixtures having at least two of the types of fuel of diesel, petrol, naphtha, butanol, kerosene, GTL (gas to liquid) or BTL (biomass to liquid) is corrected as a function of the determined viscosity.
14. Method according to at least one of the preceding claims, characterized in that the fuel is kept in the cavity (28) under an excess pressure.
15. Fuel supply system for an internal combustion engine having a device for determining the viscosity of a fuel in the fuel supply system, wherein the device has a cavity (28) which can be filled without bubbles with the fuel and in which an expeller body (30) which can be shifted from a first predetermined position (44) to a second predetermined position (42) is arranged, characterized in that the cavity (28) is integrated, parallel to a fuel line (14), into the fuel supply system, wherein the cavity (28) is connected in a fluid-conducting fashion to the fuel line (14) by means of an inflow (34) for the fuel and via a 2/2-way valve (36) as well as by means of an outflow (38) for the fuel and via a non-return valve (40).
16. Fuel supply system according to Claim 15, characterized in that the cavity (28) and the expeller body (30) are arranged and embodied in such a way that during a movement of the expeller body (30) in a gap (52) a shear flow is formed between the expeller body (30) and the cavity (28).
17. Fuel supply system according to Claim 15 or 16, characterized in that the expeller body (30) is a piston or a diaphragm piston.
18. Fuel supply system according to at least one of Claims 15 to 17, characterized in that a mechanical spring device, in particular a helical spring or a gas pressure spring (32') is arranged in the cavity (28) and embodied in such a way that this mechanical spring device moves the expeller body (30) with a predetermined movement force (54) from the first predetermined position (44) to a second predetermined position (42).
19. Fuel supply system according to at least one of Claims 15 to 18, characterized in that a mechanical translation device is arranged in the cavity (28) and embodied in such a way that this mechanical translation device moves the expeller body (30) with a predetermined speed from the first predetermined position (44) to a second predetermined position (42).
20. Fuel supply system according to at least one of Claims 15 to 19, characterized in that the device is embodied as a closed system.
21. Fuel supply system according to at least one of Claims 15 to 20, characterized by a fuel tank (10) and at least one return line (24, 26) for the fuel, wherein fuel is fed into a circuit via the fuel tank (10), the fuel line (14) and the return line (24, 26), and wherein the device is integrated into the circuit of the fuel.
22. Fuel supply system according to Claim 21, characterized in that the device is arranged downstream of a pump.

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